Late-opening Flowers Research Articles

An analysis of hormones and mineral nutrients in fruit from terminal and lateral racemes of two blueberry cultivars

BACKGROUND: In general, fruit that develops from early-opening flowers ripens earlier than fruit from late-opening flowers. However, the opposite has been observed in the rabbiteye blueberry cultivar “Brightwell” (Vaccinium ashei). OBJECTIVE: From the differences of endogenous hormones and mineral nutrition, with attempt to analyze the reasons for fruit from late-opening flowers on lateral racemes of “Brightwell” ripened earlier than fruit from early-opening flowers on terminal racemes. RESULTS: Fruit from late-opening flowers on lateral racemes of “Brightwell” ripened earlier than fruit from early-opening flowers on terminal racemes. This may be associated with the higher levels of giberellin 1, abscisic acid (ABA), salicylic acid, jasmonic acid, phosphorus, iron and boron in the early developmental stages, and the higher ABA level and lower giberellin 9 level in the fruit ripening stages on lateral racemes, compared with on terminal racemes. However, the fruit borne on the terminal racemes of “O’Neal” grew faster than fruit borne on lateral racemes, this may be correlated with the higher IAA, iron, manganese, zinc and boron levels, and the lower ABA level, in the early fruit developmental stages on terminal racemes, compared with on lateral racemes. CONCLUSIONS: The growth and ripening differences in fruit set at the two positions of the two blueberry cultivars may be associated with hormonal and nutritional control during fruit development.

Evolution of Autonomous Selfing in Marginal Habitats: Spatiotemporal Variation in the Floral Traits of the Distylous Primula wannanensis.

Outcrossing plant species are more likely to exhibit autonomous selfing in marginal habitats to ensure reproduction under conditions of limited pollinator and/or mate availability. Distyly is a classical paradigm that promotes outcrossing; however, little is known about the variation in floral traits associated with distylous syndrome in marginal populations. In this study, we compared the variation in floral traits including stigma and anther height, corolla tube length, herkogamy, and corolla diameter between the central and peripheral populations of the distylous Primula wannanensis, and assessed the variation of floral traits at early and late florescence stages for each population. To evaluate the potential consequences of the variation in floral traits on the mating system, we investigated seed set in each population under both open-pollinated and pollinator-excluded conditions. The flower size of both short- and long-styled morphs was significantly reduced in late-opening flowers compared with early opening flowers in both central and peripheral populations. Sex-organ reciprocity was perfect in early opening flowers; however, it was largely weakened in the late-opening flowers of peripheral populations compared with central populations. Of these flowers, disproportionate change in stigma height (elongated in S-morph and shortened in L-morph) was the main cause of reduced herkogamy, and seed set was fairly high under pollinator-excluded condition. Our results provide empirical support for the hypothesis on the evolution of delayed autonomous selfing in marginal populations of distylous species. Unsatisfactory pollinator service is likely to have promoted reproductive assurance of distylous plants with largely reduced herkogamy mimicking “homostyles.”

Flowering time determines the weight and composition of Actinidia chinensis var. chinensis ‘Zesy002’ kiwifruit

Consistently high flavour in fruit of a recently released commercial gold-fleshed kiwifruit cultivar ‘Zesy002’ is important for consumer acceptance. We hypothesised that variation in fruit weight and quality was determined during flower differentiation, and that date of flower opening and flower type (terminal or lateral) were important indicators. We determined whether time of flowering (early 5% open, mid 50% open and late 95% open) and flower type (terminal or lateral) influenced fruit weight, fruit maturity and fruit composition over two growing seasons. Fruit that developed from early-opening terminal flowers were 12–13 g heavier than those that developed from late-opening terminal flowers. Measurements in the second season suggested that this difference in fruit weight was related to ovary weight. Early-opening flowers were produced on shoots from smaller diameter canes than mid- and late-opening flowers. The soluble solids content, firmness and flesh colour of fruit was related to the period of fruit development, so late-opening flowers produced less-mature fruit as kiwifruit are harvested at a single date. Early-opening terminal and lateral flowers had significantly more outer pericarp tissue than fruit that developed from late-opening terminal flowers. This difference in tissue proportion was associated with 1–2 units higher fruit dry matter content and higher sugar:acid ratios in ripe fruit juice. Fruit from early-opening lateral flowers were smaller but had similar maturity and sugar:acid ratios to fruit from early-opening terminal flowers. These results suggest that competition during flower differentiation in spring influences the weight and composition of the ovary and fruit attributes at harvest. Hence, these attributes of ‘Zesy002’ fruit could be managed by manipulating flower development in spring.

Difference in flowering time as an isolating barrier

Although many theoretical studies have reported strong effects of different flowering times on reproductive isolation, such studies have all focused on the different flowering time within a season, and the subsequently developed models are difficult to apply to the cases of diurnal- and nocturnal-flowering species pairs. The different flowering times within a day differ from those within a season because of the simultaneous opening and closing of the flowers for each species and the carry-over of the pollen from early to later times. In this study, we consider pollinator-mediated, diurnal- and nocturnal-flowering plants and build a new model to study the effects of the different flowering times within a day on reproductive isolation. We assume two loci, each with two alleles, which determine the opening and closing times of flowers, respectively. We numerically calculate the changes in the frequencies of the gametes in a model incorporating the reductions in hybrid viability, flowering costs, recombination rate and degree of dominance at each locus. We found that the early-opening flowers had a much higher fitness than the late-opening flowers and that the maintenance of the two species was difficult even if their flowering times were not overlapping. Therefore, some other mechanisms, such as pollinator preference, may be required to explain the coexistence of closely related diurnal and nocturnal flowers.

Kiwifruit size and CPPU response are influenced by the time of anthesis

The cytokinin-active compound, N 1-(2-chloro-4-pyridyl)- N 3-phenylurea (CPPU), applied at different flowering dates, affected final ‘Hayward’ kiwifruit size. Ovaries from early opening flowers had significantly greater ( P≤0.05) length, diameter, and fresh and dry weight than late ovaries. Cell number and cell size in the inner and outer pericarp of the ovary at anthesis were similar for early and late opening flowers but core cell number was significantly higher ( P≤0.05) in the early flowers. Fruit shape and ovary dry matter percentage at harvest was unaffected by the time of anthesis. When fruitlets from both types of flowers were treated with CPPU at 15 μl l −1 there was a significant interaction, with the early flowers achieving a much larger commercial fruit size (153 g) than fruit from later flowers (126 g). CPPU-treated fruit from the two bloom dates achieved higher cell number in the outer pericarp at harvest. In contrast, the cell size in the inner pericarp of early and late untreated fruits was higher than CPPU-treated fruit. Pre-anthesis factors and early fruit growth were important in determining final fruit size.

Early reproductive failure increases nectar production and pollination success of late flowers in south Andean Alstroemeria aurea.

Fertile ramets of bumblebee-pollinated Alstroemeria aurea, a clonal perennial native to the temperate forests of the southern Andes, produce single terminal inflorescences that may bear two or more temporally non-overlapping whorls of flowers. While fruit set is commonly high (>80%) among early-opening flowers, it is usually low (<20%) among late-opening flowers within ramets. Using flowering ramets with two whorls of flowers, we examined experimentally the following related hypotheses. First, late flowers act as a reserve of ovaries, increasing their likelihood of setting seed when early fruits abort due to either pollen or resource limitation. Second, where early fruit abortion has occurred, plants may actively ensure pollination of late flowers by increasing their attractants and rewards. In a natural population, we simulated (1) lack of pollen deposition in early flowers, by excising their stigmas just before receptivity, and (2) resource limitation, by removing all the leaves from an experimental flowering ramet. Treatments were applied to individual ramets according to a 2 × 2 factorial design. We found that when early flowers failed to set fruit due to stigma excision, nectar secretion and particularly pollen receipt strongly increased in late flowers. Higher pollen deposition contributed significantly to the observed five-fold increase in seed output of late flowers. Fruit and seed set from early flowers were more negatively affected by defoliation than that from late flowers. Defoliation did not interfere with a ramet's capacity to increase late reproductive output when early reproduction failed. These results support the assertion that late flowers act as a reserve of ovaries helping a plant to cope with an unpredictable environment. These results also suggest that plants may actively increase pollinator visitation by opportunistically increasing flower rewards.

A New Subgenus and Fifteen New Species of Echeandia (Anthericaceae) from Mexico and the United States

Two subgenera in Echeandia (Anthericaceae), i.e., subg. Echeandia and subg. Mscavea, are recognized based on time of flower opening, tepal shape, flower color, and habitat differences. Fifteen species are proposed. One, E. texensis, is based on four collections made near Brownsville, Texas, and is surely rare, possibly extirpated. The recognition of five species clarifies the distributional range of E. reflexa, a common species of eastern Mexico. Seven species are endemic to Guerrero and adjacent areas of Michoacin, Mexico, Morelos, and/ or Oaxaca. A key to the species of subgenus Mscavea and white-flowered species of subgenus Echeandia is provided. Echeandia, as described by Ortega (1800: 135, tab. 18), included New World species with connate anthers and scaled filaments. These traits effectively separated Echeandia and Old World Anthericum, which had free anthers and smooth or papillate filaments. With few exceptions, New World species with free anthers were included in Anthericum for the next 180 years. However, during that time, species with smooth filaments were included in Echeandia (see Weatherby, 1910), and species with scaled filaments were described in Anthericum (Baker, 1876; Greenman, 1898). Thus, for the past century or more, New World Anthericum and Echeandia were separated simply on the nature of their anthers, and the unique traits they shared were ignored. Because most New World species described in Anthericum and Echeandia share traits that are unique in Anthericaceae, including a corm and scaled filaments, they are now included in Echeandia (see Cruden, 1987, 1994), which, with 78 described species, is the second largest genus in Anthericaceae (see Chase et al., 1996; Dahlgren et al., 1985: 186). Excluded from Echeandia are approximately 20 white-flowered South American species with smooth filaments and free anthers that probably constitute an undescribed genus. Within Echeandia there are two distinct lineages, and each includes species with free anthers and others with connate anthers. The two lineages share at least two synapomorphies. First, all Echeandia have a corm that produces new storage roots and inflorescences yearly. Other Anthericaceae are rhizomatous, and only the terminal segment produces leaves and inflorescences. There is no evidence that a segment produces inflorescences in successiv years. Second, most genera in Anthericaceae s. str. have smooth and/or papillate filaments, e.g., Chlorophytum s.1. (Kativu & Nordal, 1993) and Hagenbachia (Cruden, 1987), whereas most Echeandia (63/78) have scaled filaments and those with smooth filaments occur in derived groups. In addition, anthers adapted for pollination by vibratory bees occur in both lineages and are unique in Anthericaceae s. str. In the white-flowered lineage the anthers in 21 of 25 species are connate and form a cone, and in the other 4 species the individual anthers are adapted for buzz pollination (see below). In the yellow-flowered lineage, 19 of 53 species have anther cones and in 4 additional species the individual anthers are adapted for buzz pollination. The filaments of all these species are inserted dorsally within a basipetally opening pocket, which effectively holds the anther on the same axis as the filament and probably provides the structural stability needed to support a bee while it vibrates an anther or anther cone. It is possible that connate anthers constitute a parallel apomorphy. In other Echeandia and most other Anthericaceae, the anthers are free, usually versatile, dorsifixed, and dehisce laterally. In most Chlorophytum, however, the filaments are inserted more or less basally in a deep pit, which restricts the movement of the anthers. Finally, relative to Echeandia's putative ancestor, both lineages combine a mixture of primitive and derived traits. Based on other Anthericaceae, that ancestor had white flowers, which probably opened relatively early in the morning, broadly elliptical tepals, smooth filaments, and versatile anthers that dehisced laterally. Thus, yellow flowers are apomorphic in one lineage, as are narrowly elliptical inner tepals and late opening flowers in the other. Thus, the available data are consistent with a common ancestor diverging into two lineages, which are formally recognized below as subgenera. NovoN 9: 325-338. 1999. This content downloaded from 207.46.13.124 on Sun, 11 Sep 2016 04:55:57 UTC All use subject to http://about.jstor.org/terms

No Evidence for Demographic Costs of Seed Production in the Pollen-Limited Perennial Herb Blandfordia grandiflora (Liliaceae)

Increased seed production in pollen-limited plants may result in decreases in future fecundity, growth, and/or survival, indicating that resources limit seed set in the long term. In pollen-limited Blandfordia grandiflora populations, I generated high- and low-reproductive-effort plants to examine whether increased seed production resulted in demographic costs over a 3-yr period. I used similar treatments to examine whether trade-offs occurred between seed production and corm mass within a flowering year. To examine how demographic costs might be avoided, I compared masses of leaves, roots, and corms of flowering + fruiting and nonflowering plants. I also examined whether seed production was resource limited by comparing seed abortion, production, and mass in early and late opening flowers on cross-pollinated plants and assessed the magnitude of reproductive effort (RE) in open- and cross-pollinated plants. Seed abortion, set, and mass did not differ between early and late fruits, indicating that sufficie...

The effect of inter-fruit competition, type of fruiting lateral and time of anthesis on the fruit growth of kiwifruit(Actinidia deliciosa)

The final fruit size of kiwifruit was dependent on seed number, but fruit with few seeds were proportionally smaller if in close proximity to fruit with many seeds. Fruit on the same lateral with equal seed numbers developed to similar final fruit sizes. The final size of a fruit was also partly determined by pre-anthesis factors. Late opening flowers tended to produce small fruit. A predominance (74.3%) of late flowers were found on short (terminating) laterals, while 85.4% of early flowers were carried on long (non-terminating) laterals. Differences in mean fruit size at harvest between fruit developing from early or late flowers on uniform, short laterals were as much as 31 g. This was equivalent to a reduction of about 2 g per day as anthesis was delayed. This difference was independent of fruit seed number, but a significant difference between the size of the ovary of early and late flowers was present at the beginning of fruit development. In addition, fruit produced on long laterals were bigger (10...

Timing of reproduction in a prairie legume: seasonal impacts of insects consuming flowers and seeds.

Seasonal patterns of insect damage to reproductive tissue of the legume Baptisia australis were studied for three years in native tallgrass priairie. Contrasting seasonal patterns of damage were associated with the major species of insect consumers. The moth Grapholitha tristegana (Olethreutidae) and the weevil Tychius sordidus (Curculionidae), which together infested 80-100% of developing fruits (pods), consistently damaged more seeds on average in early than in late maturing pods. But while late opening flowers were less subject to attack from moths and weevils, they were more subject to attack from chewing insects, particularly blister beetles (Epicauta fabricii, Meloidae), which destroyed >80% of all flowers and developing young pods (including moth and weevil larval inhabitants). The blister beetles arrived late in the flowering season and fed particularly on young reproductive tissue, allowing larger, older pods that had developed from early opening flowers to escape destruction. The relative abundances and impacts of blister beetles, moths, and weevils varied from year to year. Adding to the uncertainty of reproductive success of the host plant were the large and variable amounts of damage to immature buds inflicted by insects (including the blister beetles and weevil adults) and late killing frosts. Thus, timing of flowering is critical to success in seed production for B. australis. The heavy impacts of insects and weather can result in a very narrow window in time (which shifts from year to year) during which B. australis can flower with any success. The opposing pressures exerted by insects and weather on floral reproductive success may act in concert with other features of the plant's biology to foster the maintenance of considerable diversity in flowering times among individuals in local populations of B. australis.

ナルトミカンの生理障害 (果皮黄斑症) の発生に及ぼす開花時期の早晩, 幼果に対するジベレリン処理及び着果部位の影響

The occurrence of ‘Rind yellow spot’, a physiologial disorder of ‘Naruto’ (Citrus medioglobosa Hort. ex Tanaka), which appears during maturation period, was studied in relation to time of flowering and position of fruit in the tree canopy. Gibbrellic acid (GA3) spraying and shading treatments were also performed to reduce the disorder.1. Fruit developed from flowers opening early in the season matured earlier than those from late-opening flowers, and consequently were more susceptible to the disorder.2. GA treatment of young fruits in mid-June considerably reduced the occurrence of the disorder, with only a slight delay in fruit coloration and a reduction of acid concentration.3. The occurrence of the disorder was greater for fruits harvested from east-south side, upper parts or outside of the tree canopy, than those harvested from west-north side, lower parts or inside.4. Shading treatment with cheese cloth during furit development reduced the incidence, although it also slightly decreased fruit growth and delayed coloration.

Flowering in the sweet orange.

Anthesis in Navels and Valencias in the Mildura district normally takes place over a period of 5-6 weeks from late September to the end of October. The first flowers to open are terminal (distal) on leafless shoots. Flowers on leafy shoots are generally open about I week later. Terminal flowers open early, except solitary flowers on leafy shoots. The lowest (proximal) buds are next to attain anthesis, and subterminal flowers are last. Late-opening flowers have a better chance of producing fruit than those which open early, and in consequence most fruit are developed from subterminal flowers, or from those buds just below the subterminal. Most fruiting flowers open not earlier than the fourth week of the flowering season. Flowers which are slow to reach anthesis, but do not produce fruit, remain on the tree longer than flowers which develop early. Drop of flowers after blossoming is a continuous process; there does not appear to be any particular time or period of development which is critical. Flowers on the shaded side of the tree open about 1 week later than those exposed to the sunshine, but this does not result in a better set of fruit on the shaded side.